Application of synchrotron-based reciprocal-space mapping at a fixed angular position to identification of crystal symmetry of Bi4Ti3O12epitaxial thin films

Abstract

The crystal structures of Bi4Ti3O12epitaxial films with thicknesses of 50 and 3 nm were investigated using synchrotron-based diffraction. Films with (100)/(010) orientations (i.e.aandbdomains) were grown on TiO2(101) single crystals using metal–organic chemical vapor deposition. Synchrotron-based reciprocal-space mapping at a fixed angular position was applied to the determination of the crystal symmetry of the films. This method used a grazing-incidence geometry at a fixed azimuthal angle using 25 keV incident X-rays, which enabled the generation of a reciprocal-space map with a single X-ray exposure. The maps recorded about 120 and 30 diffraction spots from the 50 and 3 nm-thick samples, respectively. A two-dimensional 200 × 250 mm detector was used 133 mm downstream from the sample. The results revealed that both Bi4Ti3O12films had aB1a1 monoclinic structure or a lower crystal symmetry.